High color graphics (variously spelled Highcolor, Hicolor, Hi-color, Hicolour, and Highcolour, and known as Thousands of colors on a Macintosh) is a method of storing image information in a computer's memory such that each pixel is represented by two bytes. Usually the color is represented by all 16 bits, but some devices also support 15-bit high color.[1]

More recently, high color has been used by Microsoft to distinguish display systems that can make use of more than 8-bits per color channel (10:10:10:2 or 16:16:16:16 rendering formats) from traditional 8-bit per color channel formats,[2] this is a distinct usage from the 15-bit (5:5:5) or 16-bit (5:6:5) formats traditionally associated with the phrase high color.

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In 15-bit high color, one of the bits of the two bytes is ignored or set aside for an alpha channel, and the remaining 15 bits are split between the red, green, and blue components of the final color, like this:

Each of the RGB components has 5 bits associated, giving 25 = 32 intensities of each component, this allows 32,768 possible colors for each pixel.

The popular Cirrus Logic graphics chips of the early 1990s made use of the spare high-order bit for their so-called "mixed" video modes: with bit 15 clear, bits 0 through 14 would be treated as an RGB value as described above, while with bit 15 set, bit 0 through 7 would be interpreted as an 8-bit index into a 256-color palette (with bits 8 through 14 remaining unused.) This would have enabled display of (comparatively) high-quality color images side by side with palette-animated screen elements, but in practice, this feature was hardly used by any software.

Human eyes are more sensitive to green light. Discontinuities in the green gradient are easier to see than in the reds, and in the blues they are the hardest to see.

When all 16 bits are used, one of the components (usually green, see below) gets an extra bit, allowing 64 levels of intensity for that component, and a total of 65,536 available colors.

This can lead to small discrepancies in encoding, e.g. when one wishes to encode the 24-bit color RGB (40, 40, 40) with 16 bits (a problem common to subsampling). Forty in binary is 00101000, the red and blue channels will take the five most significant bits, and will have a value of 00101, or 5 on a scale from 0 to 31 (16.1%). The green channel, with six bits of precision, will have a binary value of 001010, or 10 on a scale from 0 to 63 (15.9%). Because of this, the color RGB (40, 40, 40) will have a slight purple (magenta) tinge when displayed in 16 bits. Note that 40 on a scale from 0 to 255 is 15.7%.

Green is usually chosen for the extra bit in 16 bits because the human eye has its highest sensitivity for green shades, for a demonstration, look closely at the following picture (note: this will work only on monitors displaying true color, i.e., 24 or 32 bits) where dark shades of red, green and blue are shown using 128 levels of intensities for each component (7 bits). Readers with normal vision should see the individual shades of green relatively easily, while the shades of red should be difficult to see, and the shades of blue are likely indistinguishable. More rarely, some systems support having the extra bit of color depth on the red or blue channel, usually in applications where that color is more prevalent (photographing of skin tones or skies, for example).

There is generally no need for a color look up table (CLUT, or palette) when in high color mode, because there are enough available colors per pixel to represent graphics and photos reasonably satisfactorily. However, the lack of precision decreases image fidelity; as a result, some image formats (e.g., TIFF) can save paletted 16-bit images with an embedded CLUT.

1.
Color depth
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For consumer video standards, such as High Efficiency Video Coding, the bit depth specifies the number of bits used for each color component. When referring to a pixel the concept can be defined as bits per pixel, which specifies the number of bits used. When referring to a component the concept can be defined as bits per component, bits per channel, bits per color. Color depth is one aspect of color representation, expressing how finely levels of color can be expressed. The definition of both color precision and gamut is accomplished with a color encoding specification which assigns a code value to a location in a color space. Comparison, same image on five different color depths, different looks, but also different file sizes. With the relatively low color depth, the value is typically a number representing the index into a color map or palette. The colors available in the palette itself may be fixed by the hardware or modifiable within the limits of the hardware, modifiable palettes are sometimes referred to as pseudocolor palettes. 1-bit color, monochrome, often black and white, compact Macintoshes, 2-bit color, CGA, gray-scale early NeXTstation, color Macintoshes, Atari ST. 12-bit color, some Silicon Graphics systems, Color NeXTstation systems, for example, in the ZX Spectrum, the picture is stored in a two-color format, but these two colors can be separately defined for each rectangular block of 8x8 pixels. A very limited but true direct color system, there are 3 bits for each of the R and G components, the normal human eye is less sensitive to the blue component than to the red or green, so it is assigned one bit less than the others. Used, amongst others, in the MSX2 system series of computers in the early to mid 1990s, do not confuse with an indexed color depth of 8bpp. High color supports 15/16-bit for three RGB colors, in 16-bit direct color, there can be 4 bits for each of the R, G, and B components, plus optionally 4 bits for alpha, enabling 4,096 different colors with 16 levels of transparency. Or in some systems there can be 5 bits per color component and 1 bit of alpha, or there can be 5 bits for red,6 bits for green and these color depths are sometimes used in small devices with a color display, such as mobile telephones. Variants with 5 or more bits per component are sometimes called high color. More expensive LCDs can display 24-bit or greater color depth, true color supports 24-bit for three RGB colors. Usually, true color is defined to mean 256 shades of red, green, the human eye can discriminate up to ten million colors. Color processing in the eye occurs through retinal cone cells which are of three types, although not corresponding to red, green and blue hues, true color can also refer to an RGB display-mode that does not need a color look-up table

2.
Binary image
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A binary image is a digital image that has only two possible values for each pixel. Typically, the two used for a binary image are black and white, though any two colors can be used. The color used for the object in the image is the foreground color while the rest of the image is the background color, in the document-scanning industry, this is often referred to as bi-tonal. Binary images are also called bi-level or two-level and this means that each pixel is stored as a single bit—i. e. The names black-and-white, B&W, monochrome or monochromatic are often used for this concept, in Photoshop parlance, a binary image is the same as an image in Bitmap mode. Binary images often arise in digital image processing as masks or as the result of operations such as segmentation, thresholding. Some input/output devices, such as printers, fax machines. A binary image can be stored in memory as a bitmap, a 640×480 image requires 37.5 KiB of storage. Because of the size of the image files, fax machine. Most binary images also compress well with simple run-length compression schemes, binary images can be interpreted as subsets of the two-dimensional integer lattice Z2, the field of morphological image processing was largely inspired by this view. An entire class of operations on binary images operates on a 3×3 window of the image and this contains nine pixels, so 512 possible values. Considering only the central pixel, it is possible to define whether it remains set or unset, examples of such operations are thinning, dilating, finding branch points and endpoints, removing isolated pixels, shifting the image a pixel in any direction, and breaking H-connections. Conways Game of Life is also an example of a 3×3 window operation, another class of operations is based on the notion of filtering with a structuring element. The structuring element is binary image, usually small, which is passed over the target image, since the pixels can only have two values, the morphological operations are erosion and dilation. Opening tends to enlarge small holes, remove objects. Closing retains small objects, removes holes, and joins objects, a very important characteristic of a binary image is the distance transform. This gives the distance of every set pixel from the nearest unset pixel, the distance transform can be efficiently calculated. It allows efficient computation of Voronoi diagrams, where each pixel in an image is assigned to the nearest of a set of points and it also allows skeletonization, which differs from thinning in that skeletons allow recovery of the original image

3.
Grayscale
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In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information. Images of this sort, also known as black-and-white, are composed exclusively of shades of gray, grayscale images are distinct from one-bit bi-tonal black-and-white images, which in the context of computer imaging are images with only two colors, black and white. Grayscale images have many shades of gray in between, but also they can be synthesized from a full color image, see the section about converting to grayscale. The intensity of a pixel is expressed within a range between a minimum and a maximum, inclusive. This range is represented in a way as a range from 0 and 1. This notation is used in papers, but this does not define what black or white is in terms of colorimetry. Another convention is to employ percentages, so the scale is then from 0% to 100%. This is used for an intuitive approach, but if only integer values are used, the range encompasses a total of only 101 intensities. Also, the notation is used in printing to denote how much ink is employed in halftoning. In computing, although the grayscale can be computed through rational numbers, image pixels are stored in binary, the precision provided by this format is barely sufficient to avoid visible banding artifacts, but very convenient for programming because a single pixel then occupies a single byte. Technical uses often require more levels, to full use of the sensor accuracy. Sixteen bits per sample is a convenient choice for such uses, the TIFF and the PNG image file formats support 16-bit grayscale natively, although browsers and many imaging programs tend to ignore the low order 8 bits of each pixel. No matter what pixel depth is used, the binary representations assume that 0 is black, a common strategy is to use the principles of photometry or, more broadly, colorimetry to match the luminance of the grayscale image to the luminance of the original color image. This also ensures that both images will have the absolute luminance, as can be measured in its SI units of candelas per square meter, in any given area of the image. Then, linear luminance is calculated as a sum of the three linear-intensity values. To encode grayscale intensity in linear RGB, each of the three primaries can be set to equal the calculated linear luminance Y, linear luminance typically needs to be gamma compressed to get back to a conventional non-linear representation. In practice, because the three components are then equal, it is only necessary to store these values once in sRGB-compatible image formats that support a single-channel representation. The ITU-R BT.709 standard used for HDTV developed by the ATSC uses different color coefficients, although these are numerically the same coefficients used in sRGB above, the effect is different because here they are being applied directly to gamma-compressed values

4.
8-bit color
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8-bit color graphics is a method of storing image information in a computers memory or in an image file, such that each pixel is represented by one 8-bit byte. The maximum number of colors that can be displayed at any one time is 256, there are two forms of 8-bit color graphics. The most common uses a palette of 256 colors, where each of the 256 entries in the palette map is given red, green. In most color maps, each color is chosen from a palette of 16,777,216 colors. But in the original VGA cards 320x200 mode,256 on-screen colors could be chosen from a palette of 262,144 colors, some older cards prior to the VGA can only choose the 256-color palette from 4,096 colors. The other form is where the 8 bits directly describe red, green and this second form is often called 8-bit truecolor, as it does not use a palette at all, and is thus more similar to the 15-bit, 16-bit, and 24-bit truecolor modes. Bit 76543210 Data R R R G G G B B Most 8-bit image formats store a local palette of 256 colors in addition to the raw image data. If such an image is to be displayed on 8-bit graphics hardware and this can result in other images on the screen having wildly distorted colors due to differences in their palettes. For this reason, on 8-bit graphics hardware, programs such as web browsers must address this issue when simultaneously displaying multiple images from different sources. Each image may have its own palette, but the colors in each image will be remapped to a single palette, currently, most graphics hardware runs in 24-bit truecolor or 32-bit truecolor, and this problem is largely a thing of the past. However, some remote desktop software can switch to 8-bit color to conserve bandwidth, planar Packed pixel 15/16-bit color 24-bit color Color depth List of palettes

5.
Indexed color
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It is a form of vector quantization compression. When an image is encoded in this way, color information is not directly carried by the pixel data, but is stored in a separate piece of data called a palette. Every element in the array represents a color, indexed by its position within the array, the individual entries are sometimes known as color registers. The image pixels do not contain the full specification of its color and this technique is sometimes referred as pseudocolor or indirect color, as colors are addressed indirectly. Perhaps the first device that supported palette colors was a frame buffer, described in 1975 by Kajiya, Sutherland. This supported a palette of 256 36-bit RGB colors, the palette itself stores a limited number of distinct colors,4,16 or 256 are the most common cases. These limits are imposed by the target architectures display adapter hardware. While 256 values can be fit into a single 8-bit byte, sometimes, 1-bit values can be used, and then up to eight pixels can be packed into a single byte, such images are considered binary images and not an indexed color image. If simple video overlay is intended through a transparent color, one entry is specifically reserved for this purpose. Some machines, such as the MSX series, had the transparent color reserved by hardware, indexed color images with palette sizes beyond 256 entries are rare. The practical limit is around 12-bit per pixel,4,096 different indices, to use indexed 16 bpp or more does not provide the benefits of the indexed color images nature, due to the color palette size in bytes being greater than the raw image data itself. Also, useful direct RGB Highcolor modes can be used from 15 bpp, if an image has many subtle color shades, it is necessary to select a limited repertoire of colors to approximate the image using color quantization. Such a palette is frequently insufficient to represent the image accurately, many early personal and home computers had very limited hardware palettes that could produce a very small set of colors. In these cases, each pixels value mapped directly onto one of these colors, well-known examples include the Apple II, Commodore 64 and IBM PC CGA, all of which included hardware that could produce a fixed set of 16 colors. In these cases, an image can encode each pixel with 4-bits, in most cases, however, the display hardware supports additional modes where only a subset of those colors can be used in a single image, a useful technique to save memory. For instance, the CGAs 320×200 resolution mode could show only four of the 16 colors at one time, as the palettes were entirely proprietary, an image generated on one platform cannot be directly viewed properly on another. Other machines of this era had the ability to generate a set of colors. Examples include the 256-color palette on Atari 8-bit machines or the 4,096 colors of the VT241 terminal in ReGIS graphics mode

6.
Palette (computing)
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In computer graphics, a palette is a finite set of colors. Palettes can be optimized to improve accuracy in the presence of software or hardware constraints. Depending on the context, the palette and related terms such as Web palette. Selected colors or picked colors, In this case, the selection, generally from a wider explicitly available full palette, is always chosen by software. For example, the standard VGA display adapter is said to provide a palette of 256 simultaneous colors from a total of 262,144 different colors, default palette or system palette, The given selected colors have been officially standardized by some body or corporation. For example, the well known Web-safe colors for use with Internet browsers, on an individual image, color map or color table, The limited color selection is stored inside the given indexed color image file. For example, the registers of the Commodore Amiga are known both as their color palette and their CLUT, depending on sources. GUI palettes An arrangement of a set of user or system colors that can be chosen. In such cases, the color palette or user color palette are common equivalents. This usage resembles a true artists palette, a palette for choosing colors can be also a floating palette. An application can, in turn, show different image thumbnails in a mosaic on screen. It is obvious that the program cannot load all the adaptive palettes of every displayed image thumbnail at the time in the hardware color registers. A solution is to use a unique, common master palette or universal palette and this is done by selecting colors in such way that the master palette comprises a full RGB color space in miniature, limiting the possible levels that the red, green and blue components may have. This kind of arrangement is referred as a uniform palette. The normal human eye has sensibility to the three colors in different degrees, the more to the green, the less to the blue. So RGB arrangements can take advantage of this by assigning more levels for the green component and it is more general to use only 6R×6G×6B =216, 6R×8G×5B =240 or 6R×7G×6B =252, which leave room for some reserved colors. This way, and with further dithering, the color image can nearly match the original. But this creates a heavy dependence between the pixels and its adaptive palette

7.
RGB color model
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The RGB color model is an additive color model in which red, green and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three primary colors, red, green and blue. Before the electronic age, the RGB color model already had a theory behind it. Thus an RGB value does not define the same color across devices without some kind of color management, typical RGB input devices are color TV and video cameras, image scanners, video games, and digital cameras. Typical RGB output devices are TV sets of technologies, computer and mobile phone displays, video projectors, multicolor LED displays. Color printers, on the hand are not RGB devices. This article discusses concepts common to all the different color spaces that use the RGB color model, to form a color with RGB, three light beams must be superimposed. Each of the three beams is called a component of color, and each of them can have an arbitrary intensity, from fully off to fully on. The RGB color model is additive in the sense that the three beams are added together, and their light spectra add, wavelength for wavelength. This is essentially opposite to the color model that applies to paints, inks, dyes. When the intensities for all the components are the same, the result is a shade of gray, darker or lighter depending on the intensity. When the intensities are different, the result is a colorized hue, a secondary color is formed by the sum of two primary colors of equal intensity, cyan is green+blue, magenta is red+blue, and yellow is red+green. The RGB color model itself does not define what is meant by red, green and blue colorimetrically, and so the results of mixing them are not specified as absolute, but relative to the primary colors. When the exact chromaticities of the red, green and blue primaries are defined, the normal three kinds of light-sensitive photoreceptor cells in the human eye respond most to yellow, green, and violet light. As an example, suppose that light in the range of wavelengths enters the eye. Light of these wavelengths would activate both the medium and long wavelength cones of the retina, but not equally—the long-wavelength cells will respond more, the difference in the response can be detected by the brain, and this difference is the basis of our perception of orange. Thus, the appearance of an object results from light from the object entering our eye and stimulating the different cones simultaneously. The first experiments with RGB in early color photography were made in 1861 by Maxwell himself, to reproduce the color photograph, three matching projections over a screen in a dark room were necessary

8.
Macintosh
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The Macintosh (/ˈmækᵻntɒʃ/ MAK-in-tosh, is a series of personal computers designed, developed, and marketed by Apple Inc. Steve Jobs introduced the original Macintosh computer on January 24,1984 and this was the companys first mass-market personal computer featuring an integral graphical user interface and mouse. This first model was renamed to Macintosh 128k for uniqueness amongst a populous family of subsequently updated models which are also based on Apples same proprietary architecture. Since 1998, Apple has largely phased out the Macintosh name in favor of Mac, Macintosh systems still found success in education and desktop publishing and kept Apple as the second-largest PC manufacturer for the next decade. In the 1990s, improvements in the rival Wintel platform, notably with the introduction of Windows 3.0, then Windows 95, gradually took market share from the more expensive Macintosh systems. The performance advantage of 68000-based Macintosh systems was eroded by Intels Pentium, even after a transition to the superior PowerPC-based Power Macintosh line in 1994, the falling prices of commodity PC components and the release of Windows 95 saw the Macintosh user base decline. In 1998, after the return of Steve Jobs, Apple consolidated its multiple consumer-level desktop models into the all-in-one iMac G3, since their transition to Intel processors in 2006, the complete lineup is entirely based on said processors and associated systems. Its current lineup comprises three desktops, and three laptops and its Xserve server was discontinued in 2011 in favor of the Mac Mini and Mac Pro. Apple also develops the operating system for the Mac, currently macOS version 10.12 Sierra, Macs are currently capable of running non-Apple operating systems such as Linux, OpenBSD, and Microsoft Windows with the aid of Boot Camp or third-party software. Apple does not license macOS for use on computers, though it did license previous versions of the classic Mac OS through their Macintosh clone program from 1995 to 1997. The Macintosh project was begun in 1979 by Jef Raskin, an Apple employee who envisioned an easy-to-use, in 1978 Apple began to organize the Apple Lisa project, aiming to build a next-generation machine similar to an advanced Apple III or the yet-to-be-introduced IBM PC. In 1979, Steve Jobs learned of the work on graphical user interfaces taking place at Xerox PARC. He arranged a deal in which Xerox received Apple stock options in return for which Apple would license their designs, the basic layout of the Lisa was largely complete by 1982, at which point Jobs continual suggestions for improvements led to him being kicked off the project. At the same time that the Lisa was becoming a GUI machine in 1979, the design at that time was for a low-cost, easy-to-use machine for the average consumer. Raskin was authorized to start hiring for the project in September 1979 and his initial team would eventually consist of himself, Howard, Joanna Hoffman, Burrell Smith, and Bud Tribble. Smiths design used fewer RAM chips than the Lisa, which production of the board significantly more cost-efficient. Though there were no memory slots, its RAM was expandable to 512 kB by means of soldering sixteen IC sockets to accept 256 kb RAM chips in place of the factory-installed chips. The final products screen was a 9-inch, 512x342 pixel monochrome display, burrels innovative design, combining the low production cost of an Apple II with the computing power of Lisas Motorola 68000 CPU, began to receive Jobs attentions

9.
Computer
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A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. The ability of computers to follow a sequence of operations, called a program, such computers are used as control systems for a very wide variety of industrial and consumer devices. The Internet is run on computers and it millions of other computers. Since ancient times, simple manual devices like the abacus aided people in doing calculations, early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms. More sophisticated electrical machines did specialized analog calculations in the early 20th century, the first digital electronic calculating machines were developed during World War II. The speed, power, and versatility of computers has increased continuously and dramatically since then, conventionally, a modern computer consists of at least one processing element, typically a central processing unit, and some form of memory. The processing element carries out arithmetic and logical operations, and a sequencing, peripheral devices include input devices, output devices, and input/output devices that perform both functions. Peripheral devices allow information to be retrieved from an external source and this usage of the term referred to a person who carried out calculations or computations. The word continued with the same meaning until the middle of the 20th century, from the end of the 19th century the word began to take on its more familiar meaning, a machine that carries out computations. The Online Etymology Dictionary gives the first attested use of computer in the 1640s, one who calculates, the Online Etymology Dictionary states that the use of the term to mean calculating machine is from 1897. The Online Etymology Dictionary indicates that the use of the term. 1945 under this name, theoretical from 1937, as Turing machine, devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was probably a form of tally stick, later record keeping aids throughout the Fertile Crescent included calculi which represented counts of items, probably livestock or grains, sealed in hollow unbaked clay containers. The use of counting rods is one example, the abacus was initially used for arithmetic tasks. The Roman abacus was developed from used in Babylonia as early as 2400 BC. Since then, many forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, the Antikythera mechanism is believed to be the earliest mechanical analog computer, according to Derek J. de Solla Price. It was designed to calculate astronomical positions and it was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC

10.
Pixel
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The address of a pixel corresponds to its physical coordinates. LCD pixels are manufactured in a grid, and are often represented using dots or squares. Each pixel is a sample of an image, more samples typically provide more accurate representations of the original. The intensity of each pixel is variable, in color imaging systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black. The word pixel is based on a contraction of pix and el, the word pixel was first published in 1965 by Frederic C. Billingsley of JPL, to describe the elements of video images from space probes to the Moon. Billingsley had learned the word from Keith E. McFarland, at the Link Division of General Precision in Palo Alto, McFarland said simply it was in use at the time. The word is a combination of pix, for picture, the word pix appeared in Variety magazine headlines in 1932, as an abbreviation for the word pictures, in reference to movies. By 1938, pix was being used in reference to pictures by photojournalists. The concept of a picture element dates to the earliest days of television, some authors explain pixel as picture cell, as early as 1972. In graphics and in image and video processing, pel is often used instead of pixel, for example, IBM used it in their Technical Reference for the original PC. A pixel is generally thought of as the smallest single component of a digital image, however, the definition is highly context-sensitive. For example, there can be printed pixels in a page, or pixels carried by electronic signals, or represented by digital values, or pixels on a display device, or pixels in a digital camera. This list is not exhaustive and, depending on context, synonyms include pel, sample, byte, bit, dot, Pixels can be used as a unit of measure such as,2400 pixels per inch,640 pixels per line, or spaced 10 pixels apart. For example, a high-quality photographic image may be printed with 600 ppi on a 1200 dpi inkjet printer, even higher dpi numbers, such as the 4800 dpi quoted by printer manufacturers since 2002, do not mean much in terms of achievable resolution. The more pixels used to represent an image, the closer the result can resemble the original, the number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition.3 megapixels. The pixels, or color samples, that form an image may or may not be in one-to-one correspondence with screen pixels. In computing, a composed of pixels is known as a bitmapped image or a raster image

11.
Byte
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The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of used to encode a single character of text in a computer. The size of the byte has historically been hardware dependent and no standards existed that mandated the size. The de-facto standard of eight bits is a convenient power of two permitting the values 0 through 255 for one byte, the international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits, the popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit size. The unit symbol for the byte was designated as the upper-case letter B by the IEC and IEEE in contrast to the bit, internationally, the unit octet, symbol o, explicitly denotes a sequence of eight bits, eliminating the ambiguity of the byte. It is a respelling of bite to avoid accidental mutation to bit. Early computers used a variety of four-bit binary coded decimal representations and these representations included alphanumeric characters and special graphical symbols. S. Government and universities during the 1960s, the prominence of the System/360 led to the ubiquitous adoption of the eight-bit storage size, while in detail the EBCDIC and ASCII encoding schemes are different. In the early 1960s, AT&T introduced digital telephony first on long-distance trunk lines and these used the eight-bit µ-law encoding. This large investment promised to reduce costs for eight-bit data. The development of microprocessors in the 1970s popularized this storage size. A four-bit quantity is called a nibble, also nybble. The term octet is used to specify a size of eight bits. It is used extensively in protocol definitions, historically, the term octad or octade was used to denote eight bits as well at least in Western Europe, however, this usage is no longer common. The exact origin of the term is unclear, but it can be found in British, Dutch, and German sources of the 1960s and 1970s, and throughout the documentation of Philips mainframe computers. The unit symbol for the byte is specified in IEC 80000-13, IEEE1541, in the International System of Quantities, B is the symbol of the bel, a unit of logarithmic power ratios named after Alexander Graham Bell, creating a conflict with the IEC specification. However, little danger of confusion exists, because the bel is a used unit

12.
Color
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Color or colour is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. This perception of color derives from the stimulation of cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them and this reflection is governed by the objects physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically by coordinates, there may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the dimensions relates to a colours colorfulness). The photo-receptivity of the eyes of species also varies considerably from our own. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red, papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the kingdom has been found in stomatopods with up to 12 spectral receptor types thought to work as multiple dichromatic units. The science of color is sometimes called chromatics, colorimetry, or simply color science and it includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range. Electromagnetic radiation is characterized by its wavelength and its intensity, when the wavelength is within the visible spectrum, it is known as visible light. Most light sources emit light at different wavelengths, a sources spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, in each such class the members are called metamers of the color in question. The table at right shows approximate frequencies and wavelengths for various pure spectral colors, the wavelengths listed are as measured in air or vacuum. A common list identifies six main bands, red, orange, yellow, green, blue, Newtons conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, the color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Some objects not only light, but also transmit light or emit light themselves. This effect is known as color constancy, opaque objects that do not reflect specularly have their color determined by which wavelengths of light they scatter strongly. If objects scatter all wavelengths with roughly equal strength, they appear white, if they absorb all wavelengths, they appear black. Opaque objects that reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences

13.
Alpha compositing
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In computer graphics, alpha compositing is the process of combining an image with a background to create the appearance of partial or full transparency. It is often useful to render image elements in separate passes, for example, compositing is used extensively when combining computer-rendered image elements with live footage. In order to combine these image elements correctly, it is necessary to keep an associated matte for each element. To store matte information, the concept of a channel was introduced by Alvy Ray Smith in the late 1970s. In a 2D image element, which stores a color for each pixel, additional data is stored in the alpha channel with a value between 0 and 1. A value of 0 means that the pixel does not have any information and is transparent. A value of 1 means that the pixel is opaque because the geometry completely overlapped the pixel, if an alpha channel is used in an image, there are two common representations that are available, straight alpha, and premultiplied alpha. With straight alpha, the RGB components represent the color of the object or pixel, with premultiplied alpha, the RGB components represent the color of the object or pixel, adjusted for its opacity by multiplication. A more obvious advantage of this is that, in certain situations, however, the most significant advantages of using premultiplied alpha are for correctness and simplicity rather than performance, premultiplied alpha allows correct filtering and blending. In addition, premultiplied alpha allows regions of alpha blending. Assuming that the color is expressed using straight RGBA tuples. If the color were fully green, its RGBA would be, however, if this pixel uses premultiplied alpha, all of the RGB values are multiplied by 0.5 and then the alpha is appended to the end to yield. In this case, the 0.5 value for the G channel actually indicates 100% green intensity, for this reason, knowing whether a file uses straight or premultiplied alpha is essential to correctly process or composite it. Premultiplied alpha has some advantages over normal alpha blending because premultiplied alpha blending is associative. Moreover, premultiplied alpha has a representation for transparent pixels. Ordinary interpolation without premultiplied alpha leads to RGB information leaking out of fully transparent regions, when interpolating or filtering images with abrupt borders between transparent and opaque regions, this can result in borders of colors that were not visible in the original image. Errors also occur in areas of semitransparancy because the RGB components are not correctly weighted, with the existence of an alpha channel, it is possible to express compositing image operations using a compositing algebra. For example, given two image elements A and B, the most common compositing operation is to combine the images such that A appears in the foreground and this can be expressed as A over B

14.
Red
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Red is the color at the longer-wavelengths end of the spectrum of visible light next to orange, at the opposite end from violet. Red color has a predominant light wavelength of roughly 620–740 nanometers, light with a longer wavelength than red but shorter than terahertz radiation and microwave is called infrared. Red is one of the secondary colors, resulting from the combination of yellow. Traditionally, it was viewed as a primary colour, along with yellow and blue, in the RYB color space and traditional color wheel formerly used by painters. Reds can vary in shade from light pink to very dark maroon or burgundy. Red is the color of cyan. In nature, the red color of blood comes from hemoglobin, the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars, the color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the population has red hair, the color is produced by high levels of the reddish pigment pheomelanin. Since red is the color of blood, it has historically been associated with sacrifice, danger, modern surveys in the United States and Europe show red is also the color most commonly associated with heat, activity, passion, sexuality, anger, love and joy. In China, India and many other Asian countries it is the color of symbolizing happiness, since the 19th century, red has also been associated with socialism and communism. The word red is derived from the Old English rēad, the word can be further traced to the Proto-Germanic rauthaz and the Proto-Indo European root rewdʰ-. In Sanskrit, the word means red or blood. In the Akkadian language of Ancient Mesopotamia and in the modern Inuit language of Inuit, the words for colored in Latin and Spanish both also mean red. In Portuguese the word for red is vermelho, which comes from Latin vermiculus, in the Russian language, the word for red, Кра́сный, comes from the same old Slavic root as the words for beautiful—красивый and excellent—прекрасный. Thus Red Square in Moscow, named long before the Russian Revolution, in heraldry, the word gules is used for red. Red can vary in hue from orange-red to violet-red, and for each hue there is a variety of shades and tints. Red hematite powder was found scattered around the remains at a grave site in a Zhoukoudian cave complex near Beijing

15.
Green
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Green is the color between blue and yellow on the spectrum of visible light. It is evoked by light with a predominant wavelength of roughly 495–570 nm, the modern English word green comes from the Middle English and Anglo-Saxon word grene, from the same Germanic root as the words grass and grow. It is the color of living grass and leaves and as a result is the color most associated with springtime, growth, by far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their environments by taking on a green hue themselves as camouflage. Several minerals have a color, including the emerald, which is colored green by its chromium content. In surveys made in Europe and the United States, green is the color most commonly associated with nature, life, health, youth, spring, hope and envy. In Europe and the U. S. green is associated with death, sickness, or the devil. In the Middle Ages and Renaissance, when the color of clothing showed the social status, green was worn by merchants, bankers. The Mona Lisa by Leonardo da Vinci wears green, showing she is not from a noble family, Green is also the traditional color of safety and permission, a green light means go ahead, a green card permits permanent residence in the United States. It is the most important color in Islam and it was the color of the banner of Muhammad, and is found in the flags of nearly all Islamic countries, and represents the lush vegetation of Paradise. It is also associated with the culture of Gaelic Ireland. Because of its association with nature, it is the color of the environmental movement, political groups advocating environmental protection and social justice describe themselves as part of the Green movement, some naming themselves Green parties. This has led to campaigns in advertising, as companies have sold green, or environmentally friendly. The word green comes from the Middle English and Old English word grene, which, like the German word grün, has the same root as the words grass and grow. It is from a Common Germanic *gronja-, which is reflected in Old Norse grænn, Old High German gruoni, ultimately from a PIE root *ghre- to grow. The first recorded use of the word as a term in Old English dates to ca. Latin with viridis also has a genuine and widely used term for green, related to virere to grow and ver spring, it gave rise to words in several Romance languages, French vert, Italian verde. Likewise the Slavic languages with zelenъ, Ancient Greek also had a term for yellowish, pale green – χλωρός, chloros, cognate with χλοερός verdant and χλόη the green of new growth

16.
Blue
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Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres, which is between 4500 and 4950 ångströms. Blues with a frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency. Pure blue, in the middle, has a wavelength of 470 nanometers, in painting and traditional colour theory, blue is one of the three primary colours of pigments, along with red and yellow, which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green, Blue is also a primary colour in the RGB colour model, used to create all the colours on the screen of a television or computer monitor. The clear sky and the sea appear blue because of an optical effect known as Rayleigh scattering. When sunlight passes through the atmosphere, the wavelengths are scattered more widely by the oxygen and nitrogen molecules. An optical effect called Tyndall scattering, similar to Rayleigh scattering, explains blue eyes, distant objects appear more blue because of another optical effect called atmospheric perspective. Blue has been used for art and decoration since ancient times and it is the most important color in Judaism. In the Middle Ages, cobalt blue was used to colour the stained glass windows of cathedrals, beginning in the 9th century, Chinese artists used cobalt to make fine blue and white porcelain. Blue dyes for clothing were made from woad in Europe and indigo in Asia, in 1828 a synthetic ultramarine pigment was developed, and synthetic blue dyes and pigments gradually replaced mineral pigments and vegetable dyes. Pierre-Auguste Renoir, Vincent van Gogh and other late 19th century painters used ultramarine and cobalt blue not just to depict nature, in the late 18th century and 19th century, blue became a popular colour for military uniforms and police uniforms. In the 20th century, because blue was associated with harmony, it was chosen as the colour of the flags of the United Nations. Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness. In US and European public opinion polls it is the most popular colour, Blue is the colour of light between violet and green on the visible spectrum. Blues also vary in shade or tint, darker shades of blue contain black or grey, darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue, while lighter tints include sky blue, azure, and Egyptian blue. Today most blue pigments and dyes are made by a chemical process, the modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao. In heraldry, the azure is used for blue

17.
Cirrus Logic
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Cirrus Logic Inc. is a fabless semiconductor supplier that specializes in analog, mixed-signal, and audio DSP integrated circuits. As of 2015 Cirrus Logic has its headquarters in Austin, Texas, Dr. Suhas Patil founded the company as Patil Systems, Inc. in Salt Lake City in 1981, it adopted the name Cirrus Logic when it moved to Silicon Valley in 1984. Cirrus Logic has more than 1,000 patents and more than 600 products serving more than 2,500 end-customers globally, later the company was renamed as Cirrus Logic when it moved to Silicon Valley in 1984 to focus on solutions for the growing PC components market. Michael Hackworth was named president and chief officer in January 1985. It joined the Nasdaq market listing in 1989, Cirrus Logic acquired Crystal Semiconductor, a supplier of analog and mixed-signal converter ICs, in 1991. In the early 1990s, Cirrus Logic became a supplier of PC graphics chips, audio converters, david D. French joined Cirrus Logic, Inc. as president and chief operating officer in June 1998 and was named chief executive officer in February 1999. In June 2005, Cirrus Logic sold its video products operation to an investment firm, after French resigned in March 2007, Jason Rhode, formerly the vice president and general manager of Cirrus Logics Mixed Signal Audio Division, was named president and CEO in May 2007. Today, Cirrus Logic is focused on its high-precision technologies for digital signal processing components for audio, in 2014 Cirrus Logic bought Wolfson Microelectronics for £291 million. 1981 – Patil Systems Inc. is founded in Salt Lake City by Dr. Suhas Patil, Company focuses on IC solutions for the growing PC components market. 1984 – Patil Systems Inc. renamed Cirrus Logic and moves headquarters to Silicon Valley 1989 – Company goes public and is listed on the Nasdaq exchange under the ticker symbol CRUS, in the fall, company spins out its communication business unit. 2001 – Cirrus Logic announces plan to exit from magnetic storage chip business. 2001 – Cirrus Logic acquires several start-up companies with technologies in video decoding, video encoding, wireless networking,2003 – Cirrus Logic closes wireless networking operations. 2005 – Cirrus Logic sells video product assets to investment firm,2007 – Jason Rhode, formerly vice president and general manager of Cirrus Mixed-Signal Audio division, is named president and chief executive officer, replacing French who resigned in March. In July, Cirrus Logic acquires Apex Microtechnology, a provider of products for industrial. Cirrus Logic acquires audio chip company Tripath after they went bankrupt,2011 – Cirrus Logic is named to the Great Place to Work Institutes list of top small and medium-sized companies to work for in America, placing at #24. The company is named by the Austin American-Statesman as the top Central Texas employer. 2012 – Cirrus Logic appears at #9 on the Great Place to Work Institutes list of top small and medium-sized companies to work for in America, Cirrus Logic co-founder and chairman of the Board Michael Hackworth passes away in April. Company sells its product line in Tucson, Ariz. to a group of investors

18.
Chroma subsampling
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It is used in many video encoding schemes — both analog and digital — and also in JPEG encoding. Digital signals are compressed to save transmission time and reduce file size. In compressed images, for example, the 4,2,2 YCbCr scheme requires two-thirds the bandwidth of RGB and this reduction results in almost no visual difference as perceived by the viewer. Because the human system is less sensitive to the position and motion of color than luminance. At normal viewing distances, there is no perceptible loss incurred by sampling the color detail at a lower rate, in video systems, this is achieved through the use of color difference components. The signal is divided into a component and two color difference components. In human vision there are three channels for detection, and for many color systems, three channels is sufficient for representing most colors. For example, red, green, blue or magenta, yellow, but there are other ways to represent the color. In many video systems, the three channels are luminance and two chroma channels, in video, the luma and chroma components are formed as a weighted sum of gamma-corrected RGB components instead of linear RGB components. As a result, luma must be distinguished from luminance, indeed, similar bleeding can occur also with gamma =1, whence the reversing of the order of operations between gamma correction and forming the weighted sum can make no difference. The chroma can influence the luma specifically at the pixels where the subsampling put no chroma, the parts are, J, horizontal sampling reference. A, number of samples in the first row of J pixels. B, number of changes of chrominance samples between first and second row of J pixels, may be omitted if alpha component is not present, and is equal to J when present. This notation is not valid for all combinations and has exceptions, the mapping examples given are only theoretical and for illustration. Also note that the diagram does not indicate any chroma filtering, to calculate required bandwidth factor relative to 4,4,4, one needs to sum all the factors and divide the result by 12. Each of the three YCbCr components have the sample rate, thus there is no chroma subsampling. This scheme is used in high-end film scanners and cinematic post production. Note that 4,4,4 may instead be referring to RGB color space, formats such as HDCAM SR can record 4,4,4 RGB over dual-link HD-SDI

19.
Binary number
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The base-2 system is a positional notation with a radix of 2. Because of its implementation in digital electronic circuitry using logic gates. Each digit is referred to as a bit, the modern binary number system was devised by Gottfried Leibniz in 1679 and appears in his article Explication de lArithmétique Binaire. Systems related to binary numbers have appeared earlier in multiple cultures including ancient Egypt, China, Leibniz was specifically inspired by the Chinese I Ching. The scribes of ancient Egypt used two different systems for their fractions, Egyptian fractions and Horus-Eye fractions, the method used for ancient Egyptian multiplication is also closely related to binary numbers. This method can be seen in use, for instance, in the Rhind Mathematical Papyrus, the I Ching dates from the 9th century BC in China. The binary notation in the I Ching is used to interpret its quaternary divination technique and it is based on taoistic duality of yin and yang. Eight trigrams and a set of 64 hexagrams, analogous to the three-bit and six-bit binary numerals, were in use at least as early as the Zhou Dynasty of ancient China. The Song Dynasty scholar Shao Yong rearranged the hexagrams in a format that resembles modern binary numbers, the Indian scholar Pingala developed a binary system for describing prosody. He used binary numbers in the form of short and long syllables, Pingalas Hindu classic titled Chandaḥśāstra describes the formation of a matrix in order to give a unique value to each meter. The binary representations in Pingalas system increases towards the right, the residents of the island of Mangareva in French Polynesia were using a hybrid binary-decimal system before 1450. Slit drums with binary tones are used to encode messages across Africa, sets of binary combinations similar to the I Ching have also been used in traditional African divination systems such as Ifá as well as in medieval Western geomancy. The base-2 system utilized in geomancy had long been applied in sub-Saharan Africa. Leibnizs system uses 0 and 1, like the modern binary numeral system, Leibniz was first introduced to the I Ching through his contact with the French Jesuit Joachim Bouvet, who visited China in 1685 as a missionary. Leibniz saw the I Ching hexagrams as an affirmation of the universality of his own beliefs as a Christian. Binary numerals were central to Leibnizs theology and he believed that binary numbers were symbolic of the Christian idea of creatio ex nihilo or creation out of nothing. Is not easy to impart to the pagans, is the ex nihilo through Gods almighty power. In 1854, British mathematician George Boole published a paper detailing an algebraic system of logic that would become known as Boolean algebra

20.
Planar (computer graphics)
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In computer graphics, planar is the method of representing pixel colours with several bitplanes of RAM. Each bit in a bitplane is related to one pixel on the screen, unlike Chunky, Highcolour or Truecolour graphics, the whole data for an individual pixel isnt in one specific location in RAM, but spread across the bitplanes that make up the display. By splitting the data up into multiple planes, each plane could be stored on a memory chip. These chips could then be read in parallel at a slower rate, the EGA video adapter on early IBM PC computers used planar arrangement in colour graphical modes for this reason. When the later VGA was introduced, it included one non-planar mode which sacrificed memory efficiency for more convenient access, for example, on a chunky display, each byte represents one pixel. Where fewer than 256 colours are needed, planar graphics are more economical in RAM compared with 8-bit chunky graphics, as there are no unused bits in a given byte

21.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker

The RGB color model is an additive color model in which red, green and blue light are added together in various ways to …

A representation of additive color mixing. Projection of primary color lights on a white screen shows secondary colors where two overlap; the combination of all three of red, green, and blue in equal intensities makes white.

The first permanent color photograph, taken by J.C. Maxwell in 1861 using three filters, specifically red, green, and violet-blue.